This invention relates to a tape recorder, more particularly to a tape recorder which is set to a sound reproducing/recording state when a movable chassis carrying a capstan and a reel shaft is raised.
Widely used for conventional tape recorders, such as cassette-type car stereo sets, are constructions represented by what is called a Staar system, in which a movable chassis is raised and a capstan and a pair of reel shafts are inserted into reel shaft holes bored on a cassette by setting the cassette in place. According to one such conventional construction, both a motor and the capstan are mounted on the movable chassis, and an endless belt is stretched between a motor pulley and a capstan wheel for the transmission of a turning force. In this construction, however, the motor pulley and the capstan wheel adversely rotate in the same direction, so that rolling of the tape recorder may cause irregular rotations. Recently, there has been provided a tape recorder employing an automatic reverse for a dual capstan system, in which two flywheels are rotated in opposite directions to produce an anti-rolling effect. Although these flywheels may possess an anti-rolling effect since they are so designed as to have substantially equal moments, of inertia, there is taken no measure to counter the rolling of the motor. Thus, it is impossible to obtain a satisfactory anti-rolling effect. Further, in the prior art constructions represented by the Staar system raising an lowering the movable chassis, the motor as well as the capstan and the reel shaft are disposed on the movable chassis. The motor is so heavy that the movable chassis requires a great amount of power to operate.
The inventor hereof has proposed an anti-rolling mechanism in which the flywheel and the motor pulley are directly coupled to rotate in opposite directions, with the moment of inertia I.sub.F of the flywheel given as follows: EQU I.sub.F =I.sub.M .multidot.n=I.sub.M .multidot.(.omega..sub.M /.omega..sub.F).
here
I.sub.M : moment of inertia of motor, PA1 .omega..sub.M : angular velocity of motor, PA1 .omega..sub.F : angular velocity of flywheel, PA1 n: ratio of rotation.
Although capable of giving a satisfactory anti-rolling effect, this mechanism is supposed to be susceptible to irregular rotations due to deformation of a rubber tire around the outer periphery of the flywheel, which may be caused after a prolonged stay in a stop state, because the flywheel is always pressed against the motor.